The daemon in rsync 3.1.2, and 3.1.3-development before 2017-12-03, does not check for fnamecmp filenames in the daemon_filter_list data structure (in the recv_files function in receiver.c) and also does not apply the sanitize_paths protection mechanism to pathnames found in "xname follows" strings (in the read_ndx_and_attrs function in rsync.c), which allows remote attackers to bypass intended access restrictions.
https://git.samba.org/?p=rsync.git%3Ba=commit%3Bh=5509597decdbd7b91994210f700329d8a35e70a1
https://git.samba.org/?p=rsync.git%3Ba=commit%3Bh=70aeb5fddd1b2f8e143276f8d5a085db16c593b9
https://lists.debian.org/debian-lts-announce/2017/12/msg00020.html